BELFAST (Reuters) - Martin McGuinness, the former Irish Republican Army commander who laid down his arms and turned peacemaker to help end Northern Ireland's 30-year conflict, died on Tuesday after a decade as deputy first minister of the British province.

As a young street fighter in Londonderry and later as a politician and statesman, McGuinness saw his mission as defending the rights of the Catholic minority against the pro-British Protestants who for decades dominated Northern Ireland.

But for his critics, that cause was never enough to justify the IRA's campaign of bombings and shootings that killed hundreds of British soldiers and civilians.

In his later years McGuinness was hailed as a peacemaker for negotiating the 1998 peace deal, sharing power with his bitterest enemy and shaking hands with the Queen, though the gestures were condemned by some former comrades as treachery.

He was forced to step down in January, a number of months before a planned retirement, because of an undisclosed illness.

At the time a frail and emotional McGuinness told a large group of supporters gathered outside his home in the Bogside area of Northern Ireland's second city that it broke his heart that he had to bow out of politics.

"I don't really care how history assesses me, but I'm very proud of where I've come from," McGuinness told Irish national broadcaster RTE.

He is survived by his wife, Bernadette, and four children.

IRA COMMANDER

Born on May 23, 1950 in Londonderry, McGuinness in childhood experienced the contempt which many of the pro-British Protestant government had for the Catholic Irish minority who dreamt of joining with the Irish Republic to the south.

A trainee butcher, McGuinness abandoned his apprenticeship in 1970 to join the IRA as the guerrilla group began its 30-year campaign against British rule that Catholics found increasingly intolerable. He swiftly rose to become a senior commander.

McGuinness later admitted he was second-in-command of the IRA in Londonderry on "Bloody Sunday" - the day in 1972 when British troops in the city killed 14 unarmed marchers, ushering in the most intense phase of the Troubles.

A British government inquiry found McGuinness was probably armed with a sub-machine gun that day, but that he did nothing to justify the troops' decision to open fire on the marchers.

In 1973 he was convicted by the Irish Republic's courts of being an IRA member after being stopped in a car packed with explosives and bullets and was briefly jailed.

Fellow nationalist inmates recall him as a fierce football player in the exercise yard.

He spent years on the run and was banned from entering Britain in 1982, during the IRA's bombing campaign there, under the prevention of terrorism act.

POLITICS AND PEACE

During the 1980s McGuinness emerged alongside Gerry Adams as a key architect in the electoral rise of Sinn Fein, the IRA's political ally, advocating a strategy of combining the use of the ballot box with that of the Armalite rifle.

First elected as a member of the Northern Ireland assembly in 1982, McGuinness played a crucial role in keeping the more militant wing of the IRA on board as elements of the leadership secretly probed the possibility of a negotiated settlement.

Following the IRA's second ceasefire in 1997, McGuinness became Sinn Fein's chief negotiator in peace talks that led to the landmark 1998 Good Friday peace accord.

Nine years later, the rise of Sinn Fein to become Northern Ireland's largest Irish nationalist party allowed McGuinness to become Deputy First Minister in the power-sharing government with bitter enemy Ian Paisley, the firebrand preacher many Catholics see as a key player in the genesis of the conflict.

McGuinness surprised many by forming a close working relationship with Paisley, the media dubbing the pair "the Chuckle Brothers". In 2012 he shook hands with Queen Elizabeth at a charity event in Belfast.

Such gestures alienated many former comrades who call him a traitor for helping to run the province while the Union Jack was still flying over it. McGuinness countered it was a stepping stone to their goal of a united Ireland.

Over the past decade, Sinn Fein has focused much of its resources on the Republic of Ireland, where it has grown from five to 23 seats of the 166-seat parliament in a decade.

A non-smoker, virtual teetotal and keen fisherman, McGuinness briefly moved south in 2011 for a failed run at Ireland's largely ceremonial presidency, wining just under 15 percent of the vote.

McGuinness leaves Northern Ireland at peace and hands over to a new generation with Sinn Fein a major political force across the island, and his dream of a united Ireland inching closer after the party recorded its best ever result in an election three weeks before his death.